#!/bin/bash
#
# Copyright 2016 The Kubernetes Authors All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Set PROGram name
PROG=${0##*/}
########################################################################
#+
#+ NAME
#+     $PROG - Fast forward a branch to master via merge
#+
#+ SYNOPSIS
#+     $PROG  [--nomock] <branch> [master object]
#+     $PROG  [--helpshort|--usage|-?]
#+     $PROG  [--help|-man]
#+
#+ DESCRIPTION
#+     $PROG fast forwards a K8s release branch to [master object] (defaults to
#+     HEAD and then prepares the branch as a K8s release branch:
#+     * Run hack/update-all.sh to ensure compliance of generated files
#+
#+
#+ OPTIONS
#+     [--nomock]                 - Actually push this upstream
#+     [--help | -man]            - display man page for this script
#+     [--usage | -?]             - display in-line usage
#+
#+ EXAMPLES
#+     $PROG release-1.3          - Resync master@HEAD onto release-1.3 branch
#+     $PROG release-1.3 39d0135e - Resync master@39d0135e onto release-1.3
#+                                  branch
#+
#+ FILES
#+
#+ SEE ALSO
#+     lib/common.sh              - base function definitions
#+     lib/gitlib.sh              - git function definitions
#+
#+ BUGS/TODO
#+
########################################################################
# If NO ARGUMENTS should return *usage*, uncomment the following line:
usage=${1:-yes}

source $(dirname $(readlink -ne $BASH_SOURCE))/lib/common.sh
source $TOOL_LIB_PATH/gitlib.sh

# Set positional args
RELEASE_BRANCH=${POSITIONAL_ARGV[0]}
MASTER_OBJECT=${POSITIONAL_ARGV[1]:-"origin/master"}

# Check branch format
[[ $RELEASE_BRANCH =~ $BRANCH_REGEX ]] || common::exit 1 "Invalid branch name!"

# Branch Exists
gitlib::branch_exists $RELEASE_BRANCH \
 || common::exit 1 "$RELEASE_BRANCH doesn't exist.  Exiting..."

##############################################################################
# Initialize logs
##############################################################################
# Initialize and save up to 10 (rotated logs)
MYLOG=/tmp/$PROG.log
common::logfileinit $MYLOG 10
# BEGIN script
common::timestamp begin

gitlib::repo_state || common::exit 1

###############################################################################
# MAIN
###############################################################################
BASEDIR="/usr/local/google/$USER"
# WORK/BUILD area
WORKDIR=$BASEDIR/$PROG-$RELEASE_BRANCH
# Go tools expect the kubernetes src to be under $GOPATH
export GOPATH=$WORKDIR
# TREE_ROOT is working branch/tree
TREE_ROOT=$WORKDIR/src/k8s.io/kubernetes
# The real deal?
if ((FLAGS_nomock)); then
  DRYRUN_FLAG=""
else
  DRYRUN_FLAG=" --dry-run"
fi

logecho
logecho "Follow along in detail: tailf $MYLOG"

##############################################################################
common::stepheader "SESSION DETAILS"
##############################################################################
logecho "NOTE: This is a${DRYRUN_FLAG:-"n ACTUAL"} run!"

##############################################################################
common::stepheader "SYNC A WORKING REPO"
##############################################################################
if [[ -d $WORKDIR ]]; then
  common::askyorn "$WORKDIR exists.  Delete" || common::exit 1 "Exiting..."
  logrun rm -rf $WORKDIR || common::exit 1 "Exiting..."
fi

logrun mkdir -p $WORKDIR
gitlib::sync_repo $K8S_GITHUB_SSH $TREE_ROOT || common::exit 1 "Exiting..."
logrun cd $TREE_ROOT

##############################################################################
common::stepheader "CHECK GIT PUSH ACCESS"
##############################################################################
# TODO: capture state of access without forcing us into a prompt I have to 
#       expose.
logecho -n "Checking git push access (verbosely to accept password if needed)"
logrun -v git push -q --dry-run $K8S_GITHUB_SSH || common::exit 1 "Exiting..."

##############################################################################
common::stepheader "CHECK OUT BRANCH"
##############################################################################
logecho -n "Checking out $RELEASE_BRANCH: "
logrun -s git checkout -b $RELEASE_BRANCH origin/$RELEASE_BRANCH \
 || common::exit 1 "Exiting..."

##############################################################################
common::stepheader "MERGE AND UPDATE"
##############################################################################
logecho -n "Merging $MASTER_OBJECT into $RELEASE_BRANCH branch: "
logrun -s git merge -X ours $MASTER_OBJECT

# TODO: This is actually broken until #27992 lands
logecho -n "update-all.sh: "
logrun -s hack/update-all.sh

if [[ -n "$(git status -s)" ]]; then
  logecho -n "Commit changes: "
  logrun git add -A
  logrun -s git commit -am "update-all.sh." \
    || common::exit 1 "Exiting..."
fi

##############################################################################
common::stepheader "PUSH UPSTREAM"
##############################################################################
logecho "Go look around in $TREE_ROOT to make sure things look ok:"
logecho "# Any files left uncommitted?"
logecho "* git status -s"
logecho "# What does the commit look like?"
logecho "* git show"
logecho

if common::askyorn -e "OK to push now"; then
  # Finally push it upstream
  logecho -n "Pushing$DRYRUN_FLAG $RELEASE_BRANCH branch upstream: "
  logrun -s git push $DRYRUN_FLAG origin $RELEASE_BRANCH:$RELEASE_BRANCH
fi

logecho
logecho "$WORKDIR left intact for reviewing"

# END script
common::timestamp end
